Research On Optimization Theories Of Parameters In Blast Casting-Dragline Stripping Technology

In order to scientific design blast casting dragline stripping technology parameters, according to surface mining theories and technical characteristics of dragline stripping technology, integrated methods of field research, theoretical analysis, numerical simulation and field test were adopted. This was to reveal the basic laws of blast casting dragline stripping technology, propose the optimum design method for parameters of dragline working face, high bench blast casting and blast casting bench, put forward optimization theories of dragline stripping system reliability, and then construct the optimum design theory system of parameters of blast casting and dragline stripping technology.Firstly, based on the formation process and development law of stope space, and the space-time relations of working face advance, the laws of working face advance and coordinated development of mining engineering were put forward. The periodicities of dragline stripping, working-line advance, and change processes of spare coal quantities were revealed.Then, the calculation model of critical height for dragline working bench was proposed. The relationships between dragline’s operation efficiencies and heights, weights of dragline working bench were discovered. A non-linear programming model was built for optimizing working bench parameters, and the dynamic adjusting method of dragline working bench height was presented. In addition, from the perspective of the application experience, the intelligent design method of high bench blast casting parameters based on weighted clustering method was presented, cracking mechanism of pre-splitting blasting was analyzed, and the design method of large diameter and deep hole pre-splitting blasting parameters was brought forward. The prediction model of muckpile shape of blast casting was created. Furthermore, a relationship model of blast casting bench parameters and stripping and mining cost was established using regression analysis. The constraint conditions of blast casting bench parameters were given. The multi-objective optimization design model of blast casting bench parameters was established and the solution method of the multi-objective optimization model based on NSGA-II was proposed.Finally, according to the system reliability theory, new concepts of dragline stripping system reliability measurement were proposed. The factors of the reliability of dragline stripping system were analyzed; the dynamic adjusting method of design parameters was presented, and the prediction model of dragline’s production capacity was established with the application of generalized regression neural network. Thus, the dynamic optimization theory model of system reliability was built, and the measures related to optimize the reliability of dragline stripping system were proposed.The study of Heidaigou surface mine shows that the optimal dragline working bench height is 14.6m, the working bench weight is 118 m, the optimal working face length of blast casting is 2200 m, the bench height is 38 m, the strip width is 84 m, the slope angle of bench is 65 degrees. The assisted stripping volume of shovel-truck should be increase 0.19Mm3 as the planned monthly raw coal production capacity is 2.9Mt. Accordingly, the advance distance of the truck assisting dragline in stripping is 235.9m. The optimize results have been approved by production practice.